STRUCTURAL EFFECTS IN ELECTROCATALYSIS - OXIDATION OF D-GLUCOSE ON SINGLE-CRYSTAL PLATINUM-ELECTRODES IN ALKALINE-SOLUTION

Electrochemical oxidation of D-glucose has been studied in 0.1 M NaOH on single crystal platinum electrodes with thirteen different orientations. The reaction rate depends strongly on the crystallographic orientation of the electrode surface. For most of the surfaces investigated, three voltammetric peaks were observed in the potential region of hydrogen adsorption, the double layer region and the region of anodic film formation. The most active surface is Pt(111). The poisoning adsorbates seem to be less strongly adsorbed on this plane than on Pt(100) or Pt(110). The (100) and (111) oriented steps cause a decrease of the activity of Pt(111). A strongly bound species appears to be adsorbed preferentially on the step sites. Its oxidation was found to coincide with the Pt(OH)ads layer formation.